Between April-September 1999 an unusually high number of acute aseptic meningitis was reported in six North Eastern counties of Romania. At the end of 1999 summer the epidemic area extended in South Romania including the Capital City Bucharest. The total number of cases surpassed 5500. The majority of confirmed cases were young children under 15 years of age. More than 1800 cases were registered in the same interval in the neighboring Republic of Moldavia. We report the isolation of ECHO 30 virus from 12 CSF samples of 52 tested on RD and human diploid cells. A small case control study identified high seroneutralization titers confirming a recent ECHO 30 infection in 74% of patient's samples and in 54% of samples from control children tested. The time spent outdoors and poor hygiene practices were prominent risk factors for transmission.